U.S. patent application number 14/449515 was filed with the patent office on 2016-02-04 for cannula assembly.
The applicant listed for this patent is Patrick Cohen. Invention is credited to Patrick Cohen.
Application Number | 20160030079 14/449515 |
Document ID | / |
Family ID | 55178819 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160030079 |
Kind Code |
A1 |
Cohen; Patrick |
February 4, 2016 |
CANNULA ASSEMBLY
Abstract
The invention provides an improved cannula assembly comprising a
first cannula having a first length and first inner diameter, the
first cannula having at least a flexible distal portion; a trochar
having a second length and second diameter, the trochar having a
sharp distal position capable of puncturing through skin and one or
more blood vessels of a patient and sized such that the trochar may
be inserted within the first cannula and extend beyond the flexible
distal portion thereof; and at least one flexible second cannula
for insertion in the first cannula, each second flexible cannula
sized to extend beyond the distal portion of the first cannula for
a predetermined length.
Inventors: |
Cohen; Patrick; (Maytar,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cohen; Patrick |
Maytar |
|
IL |
|
|
Family ID: |
55178819 |
Appl. No.: |
14/449515 |
Filed: |
August 1, 2014 |
Current U.S.
Class: |
604/507 ;
604/164.11 |
Current CPC
Class: |
A61M 25/0606 20130101;
A61M 5/158 20130101; A61M 2240/00 20130101; A61M 25/0637 20130101;
A61M 2025/0681 20130101 |
International
Class: |
A61B 17/34 20060101
A61B017/34; A61M 5/158 20060101 A61M005/158 |
Claims
1. An improved cannula assembly, comprising: cannula having a first
length and first inner diameter, the first cannula having at least
a flexible distal portion; a trochar having a second length and
second diameter, the trochar having a sharp distal position capable
of puncturing through skin and into a blood vessel of a patient and
sized such that the trochar may be inserted within the first
cannula and extend beyond the distal portion thereof; and at least
one flexible second cannula for insertion in the first cannula, the
second flexible cannula sized to extend beyond the distal portion
of the first cannula for a predetermined length within the blood
vessel of the patient.
2. An improved cannula according to claim 1, wherein the
predetermined length of the second cannula is chosen to avoid
collapse of a patient's blood vessel in which the cannula is
inserted.
3. An improved cannula assembly according to claim 1, wherein the
cannula has a proximal end sized to accept a syringe or an
intravenous solution adapter.
4. An improved cannula assembly according to claim 1, wherein the
assembly is sized for use in a pediatric patient.
5. An improved cannula assembly according to claim 1, wherein the
assembly is sized for use in a neonatal patient.
6. A method for infusing a fluid into or withdrawing a fluid from a
blood vessel of a patient, comprising: providing a cannula assembly
having a first cannula having a first length and a first inner
diameter, the first cannula having at least a flexible distal
portion, a trochar having a second length and a second diameter,
the trochar having a sharp distal end capable of puncturing through
skin and a blood vessel of a patient, the trochar sized to insert
and slide within the first cannula and extend beyond the distal
portion thereof, and at least one flexible second cannula for
insertion in the first cannula, each second cannula sized to extend
beyond the distal portion of the first cannula for a predetermined
length; inserting the trochar into the first cannula such that the
sharp distal tip extends beyond the distal portion of the first
cannula; inserting the first cannula and the trochar into a blood
vessel of a patient by puncturing through skin into the blood
vessel of the patient; withdrawing the trochar from the first
cannula; and inserting the second cannula into the first cannula
such that the distal end of the second cannula extends a
predetermined distance in the blood vessel of the patient beyond
the distal end of the first cannula.
7. A method in accordance with claim 6, further comprising
connecting a syringe to a proximal end of the first cannula and
withdrawing blood from the patient.
8. A method in accordance with claim 6, further comprising
connecting a liquid dispenser to a proximal end of the first
cannula and infusing a liquid into the blood vessel of the
patient.
9. A method in accordance with claim 6, wherein the second cannula
is withdrawn from the first cannula after use, leaving the first
cannula in the blood vessel of the patient and capable of accepting
another second cannula for repeated access to the blood vessel.
Description
FIELD OF THE INVENTION
[0001] This invention related to medical devices, and more
specifically, to cannula assemblies for transferring a fluid into
or out of a body cavity, such as a blood vessel.
BACKGROUND OF THE INVENTION
[0002] Many medical procedures require access to a body cavity,
such as a blood vessel, in order to deliver substances to the
cavity or to withdraw fluids from the cavity. For example, a vein
may be accessed in order to administer fluids and drugs, or for
drawing blood for analyses. Accessing a body cavity, such as a
blood vessel, often involves introducing a catheter onto a cannula
and pushing the cannula tip through the skin and into the body
until the tip of the cannula and the catheter are positioned inside
the lumen of the vein or artery. The cannula or hollow needle is
then removed while leaving the flexible catheter in place, which
thus forms a conduit for the infusion or withdrawal of fluids
between the vessel and the exterior of the body. When multiple
transfers of fluid into or out of a vessel are required, the
catheter can be left in place in order to reduce the need to
reinsert the cannula or needle into the body, which is inconvenient
and often painful for the patient.
[0003] One way to avoid repeated insertion of a needle into the
vein is to use a venous or arterial cannula, which is usually a
thin tube, the distal end of which is inserted through the skin
into a blood vessel and maintained indwelling in the blood vessel
with the proximal end of the tube being accessible on the skin
surface. A trocar is used to puncture the vein and insert the
silicon cannula that remains in the vein. Common complications
associated with cannulation of a blood vessel include hematoma
(accumulation and dotting of blood due to failure to puncture the
blood vessel when the cannula is inserted), infiltration (delivery
of an infusate to subcutaneous tissue instead of the vein),
embolism (caused by air, a thrombus, or fragment of a catheter
breaking off and entering the venous system), or phlebitis
(inflammation of the vein resulting from mechanical or chemical
irritation or from an infection). These complications are often
more serious in children and elderly patients repeatedly exposed to
cannula insertion and withdrawal.
[0004] In addition, in order to withdraw blood and because one
cannot use a cannula that is already in a vein, one must repuncture
again at least once a day for every hospitalized patient. That is
the main difficulty and cause of hematomas and infections. Repeated
punctures particularly in the elderly and in children, may cause
the veins to collapse, making it difficult to find a suitable vein
from which to withdraw blood.
SUMMARY OF THE INVENTION
[0005] The objects of the inventions and disadvantages of prior
devices are overcome by the present invention, which provides an
improved cannula assembly, comprising a first cannula having a
first length and first inner diameter, the first cannula having at
least a flexible distal portion; a trochar having a second length
and second diameter, the trochar having a sharp distal position
capable of puncturing through skin and one or more blood vessels of
a patient and sized such that the trochar may be inserted within
the first cannula and extend beyond the flexible distal portion
thereof; and at least one flexible second cannula for insertion in
the first cannula, each second flexible cannula sized to extend
beyond the distal portion of the first cannula for a predetermined
length.
[0006] The invention further provides a method of inserting a
cannula into a blood vessel to deliver a fluid to or withdraw a
fluid from a blood vessel or other body cavity comprising providing
a cannula assembly having a first cannula having a first length and
a first inner diameter, the first cannula having at least a
flexible distal portion, a trochar having a second length and a
second diameter, the trochar having a sharp distal end capable of
puncturing through skin and one or more blood vessels of a patient,
the trochar sized such that the trochar may be inserted within the
first cannula and extend beyond the flexible distal portion
thereof, and at least one flexible second cannula for insertion in
the first cannula, each second cannula sized to extend beyond the
distal portion of the first cannula for a predetermined length;
inserting the trochar into the first cannula such that the sharp
distal tip or end extends beyond the distal end of the first
cannula; inserting the first cannula and the trochar into a blood
vessel of a patient by puncturing through skin into the blood
vessel of the patient; withdrawing trochar from the first cannula;
and inserting the second cannula into the first cannula such that
the distal end of the second cannula extends predetermined distance
in the blood vessel of the patient beyond the distal end of the
first cannula.
[0007] The original cannula already has the sharp metal trocar and
is used to puncture the skin and serve as a guide for the cannula.
The first cannula remains in place, and another second cannula is
inserted each time another blood sample is needed or desired. This
saves the patient from multiple punctures and the system, may be
sized for use with adult, pediatric, neonatal or elderly
patients.
[0008] The system of the invention may be used, for example, for
collecting a blood sample from a blood vessel, or infusing a liquid
such as an intravenous fluid into a blood vessel. The system of the
invention is particularly suited when repeated withdrawals of fluid
are to be performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In order to understand the invention and to see how it may
be carried out in practice, embodiments will now be described, by
way of non-limiting example only, with reference to the
accompanying drawings, in which:
[0010] FIG. 1 shows an improved cannula for withdrawing fluid from
a body cavity or delivering fluid to a body cavity, in accordance
with one embodiment of the invention;
[0011] FIG. 2 shows the trocar of the system of FIG. 1 inserted
into the cannula device of the FIG. 1;
[0012] FIG. 3a shows insertion of the tip of the trocar and cannula
of the cannula assembly of the present invention into a blood
vessel; and
[0013] FIG. 3b shows removal of blood from the blood vessel using
the improved cannula assembly of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] FIG. 1 shows a system 10 for transferring a fluid into or
out of a body cavity such as an artery, vein, or other vessel (not
shown), in accordance with one embodiment of the invention. The
system 10 comprises a cannula device 12 having a flexible cannula
14 mounted onto a holder 16. The cannula device 12 also has a
flashback chamber 18 that is used to determine when the distal end
20 of the cannula 14 is properly positioned inside a vessel by the
presence of fluid such as blood in the flashback chamber 18, as
explained below. Wings 22 on the holder 16 are used to insert the
cannula device 12 into a blood vessel and can be adhered to the
body surface using adhesive tape, for example (not shown). Fluids
can enter or leave the cannula 12 either via a side port 24 or
through a female Luer fitting 26, when a syringe or tubing (not
shown) is attached to the Luer fining 26.
[0015] As shown in FIG. 2, the device 10 further comprises a trocar
28 having a slender, rigid, hollow tubular needle portion 30, a
proximal end 32 that may be provided with a female Luer fitting 34
and a distal end terminating in a sharp pointed tip 38 suitable for
puncturing skin and blood vessels.
[0016] The system 10 further comprises one or more flexible needles
40 having a flexible tubular portion 42, a proximal end 44 provided
with a female Luer fitting 46, and a distal open end 48. The system
10 may also comprise a syringe 50 having a barrel 52 terminating in
a male Luer fitting 54 configured to mate with the female Luer
fitting 46 on the flexible needle 40, and a plunger 56. The
flexible needle 40 may be integral with the syringe 50.
[0017] In use, the trocar 28 is inserted into the cannula device
12, as shown in FIG. 2. The outer diameter of the hollow tubular
portion 30 of the trocar 28 is selected to be less than the inner
diameter of the cannula 14, so that the trocar 28 is slidable
within the cannula 14. The length of the hollow tubular portion 30
of the trocar 28 is selected to allow the tip 38 of the trocar 28
to extend beyond the tip 9 of the cannula 14 while the Luer fitting
26 of the trocar 28 is positioned in the Luer fitting 26 of the
cannula device 14.
[0018] FIGS. 3a and b show use of the system 10 for obtaining a
blood sample from a blood vessel 60. This is by way of example only
and the system 10 may be used to deliver a fluid to any body cavity
or to withdraw a fluid from a body cavity. As shown in FIG. 3a,
after insertion of the trocar 28 into the cannula device 14, the
tip 38 of the trocar 28 is used to pierce the skin surface 62. The
tip 38 with the cannula 12 is then pushed forward until the tip 38
of the trocar 28 pierces the blood vessel wall 64 and the tip 38 of
the trocar and the tip 29 of the cannula are positioned in the
blood vessel 60. Insertion of the tip 29 of the cannula inside the
blood vessel 60 is evidenced by the presence of blood in the
flashback chamber 24. When the tip 20 of the cannula is positioned
in the blood vessel the trocar 20 is removed from the cannula
device 12. The cannula device 12 can then be affixed to the skin
surface 62, for example, by taping the wings 22 to the skin surface
62. The cannula extends into a vein for a predetermined distance so
as to avoid valves located in the vein and to avoid a vacuum or
venturi effect, which is believed to be a problem with in-dwelling
venous catheters. See FIG. 3b.
[0019] Now, as shown in FIG. 3b, the flexible needle 40 is mounted
onto the syringe 50 with the plunger 56 in its depressed position.
The flexible needle 40 is then inserted into the cannula device 12
until the tip 46 of the needle 40 extends beyond the tip 20 of the
cannula 14 in the blood vessel 60. The plunger 56 can then be
pulled back causing blood 58 to fill the barrel of the syringe
50.
[0020] After removal of blood, the syringe 50 and the flexible
needle 40 are removed from the cannula device 12. The cannula
device 12 remains affixed to the skin surface 62. The Luer fitting
26 is stoppered with a stopper (not shown) to prevent loss of blood
from the blood vessel 64 or entry of pathogens into the device.
[0021] At any time when another blood sample 58 is to be withdrawn,
a new flexible needle 40 is mounted onto a new syringe 50. The
stopper (not shown) is removed and the flexible needle 40 is
inserted through the cannula device 12 into the blood vessel 64, as
shown in FIG. 3b, and the process repeated. Repeated withdrawals of
blood 58 can thus be performed without piercing the skin repeatedly
with the trocar 20 and without the need to change the cannula
device 12.
[0022] It should be apparent to a person of ordinary skill in the
art that the improved cannula assembly of the present invention
provides many advantages over prior systems. First, the use of
insertable elongated flexible cannula that extends beyond the
distal end of the assembly avoids collapse of blood vessels near
the tip of the assembly by extending a sufficient distance beyond
the tip to avoid any blood vessel narrowing that may be present.
Additionally, the flexible cannula is disposable thereby ensuring
sterility. Further, the flexible cannula can be used to infuse
fluid or medication into a vessel or to withdraw fluid or blood
samples For testing and analysis.
[0023] The invention has been described with reference to
particular embodiments, it should be understood that these
embodiments are merely illustrative of the principles and practice
of the present invention, and that various modifications will be
apparent to persons of ordinary skill in the art, and that it is
therefore intended that all search modifications are intended to be
included within the spirit and scope of the invention as defined by
the following claims.
* * * * *